IIS FTP Server Users May Experience Delayed Responses

• Microsoft Internet Information Server version 1.0

SYMPTOMS

Microsoft Internet Information Server FTP clients experience delayed responses to commands when a large number of users are logged on through FTP. This symptom occurs sporadically. File transfer speeds are not affected.

CAUSE

The default number of threads per processor (MaxPoolThreads) installed on your system is 10. This may be not be sufficient for a heavily used FTP server because some of the FTP commands use synchronous I/O, causing threads to block while they complete.

RESOLUTION

To allow more processor threads for IIS FTP clients , do the following in the registry.

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

1. Start Registry Editor (REGEDT32.EXE) and locate the following Registry subkey in the HKEY_LOCAL_MACHINE subtree:

   \SYSTEM\CurrentControlSet\Services\InetInfo\Parameters

2. From the Edit menu, select Add Value.

3. Enter the following:

         Value Name: MaxPoolThreads
         Data Type:  REG_DWORD
         String:     <Range is 0 to 0xFFFFFFFF>
   
      NOTE: A twin processor with 500 to 1000 concurrent users may require 50
      or more threads per processor to provide quick response for all FTP
      client users.
   
   

4. Choose OK and quit the Registry Editor.

5. Shut down and restart Windows NT.

STATUS

Microsoft has confirmed this to be a problem in Internet Information Server version 1.0. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.